Sulfate-attack in Concrete

Dissolved soluble sulfates in waters – e.g. in rivers, sewer units and lines – react with certain components of Portland cement to form an over-sized reaction product. The reaction product incubates in typically voids, grows, and burst out of the voids, creating delamination in the concrete. Several such accumulated processes causes a weakening of the concrete.

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Several growth of deleterious reaction products in concrete

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Crystal growths of ettringite in voids of concrete as shown by scanning electron microscopy (SEM)

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An accretion of crystalline hydration products bursting out from a void to initiate and propagate cracks.

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A 6-year old concrete placed for an airport runway was removed and replaced due to sulfate attack.